Articulated arm system for attaching different medical imaging devices to support structures in an articulated manner

ABSTRACT

The invention relates to an articulated arm system ( 20 ) for attaching different medical imaging devices ( 11 ) to support structures ( 14 ) in an articulated manner. The articulated arm comprises at least one parallelogram device ( 15   a,    15   b ) including a counterbalancing mechanism for holding the articulated arm and the device ( 11 ) supported by it in place when the device is located in the desired imaging position. The system further comprises braking and/or locking means ( 2: 22 ) which act on at least one strut bar ( 6, 7 ) of the said at least one parallelogram device ( 15   a   , 15   b ) and/or on the at least one additional strut bar ( 1 ) in order to prevent mutual linear movement of the strut bars ( 6, 7 ) of the parallelogram device, and which braking and/or locking means comprise actuators ( 3-5; 23; 24 ).

[0001] The present invention relates to an articulated arm system forattaching different medical imaging devices to support structures in anarticulated manner, the articulated arm comprising at least oneparallelogram device with at least two mutually parallel strut bars; anda counterbalancing mechanism for holding the articulated arm and thedevice supported by it in place when the device is located in thedesired imaging position. The counterbalancing mechanism preferablycomprises at least one additional strut bar and counterbalancing means.

[0002] There are already articulated arm systems of the type mentionedin the introduction on the market, one problem with which is, however,the loosening of the springs and articulations with time, due to whichthe device will not, for example, remain in place during imaging,whereby the imaging result will obviously deteriorate. Accordingly, oneimportant object of the present invention is to provide an improvedarticulated arm system for attaching different medical imaging devices,for example, devices for imaging the head area, such as intraoral andpanoramic imaging devices, to support structures in an articulatedmanner, by means of which articulated arm system is ensured, throughrelatively simple measures, that the device will stay in place duringimaging.

[0003] In order to achieve the objects of the invention, the articulatedarm system according to the first aspect of the invention for attachingdifferent medical imaging devices to support structures in anarticulated manner, the articulated arm comprising at least oneparallelogram device with at least two mutually parallel strut bars; anda counterbalancing mechanism for holding the articulated arm and thedevice supported by it in place when the device is located in thedesired imaging position, is characterised in that the system furthercomprises braking and/or locking means which act on at least one strutbar of the said at least one parallelogram device and/or on the said atleast one additional strut bar in order to prevent mutual linearmovement of the strut bars of the parallelogram device, and whichbraking and/or locking means comprise actuators.

[0004] An articulated arm system relating to a second aspect of theinvention for attaching different medical imaging devices to supportstructures in an articulated manner, the articulated arm comprising atleast one parallelogram device with at least two mutually parallel strutbars; and a counterbalancing mechanism for holding the articulated armand the device supported by it in place when the device is located inthe desired imaging position, is characterised in that thecounterbalancing mechanism is comprised of an air spring arrangedbetween one strut bar and an articulated part, which spring can belocked into the desired position, thus preventing the mutual linearmovement of the strut bars of the parallelogram device.

[0005] The invention is described in greater detail in the following,with reference to the appended drawings, in which:

[0006]FIG. 1 shows a diagrammatic side view of one embodiment of thearticulated arm system relating to the invention,

[0007]FIG. 2 shows diagrammatically an alternative embodiment of thebraking and/or locking means used in the articulated arm system relatingto the invention,

[0008]FIG. 3 shows a section along line III-III of the embodiment shownin FIG. 2, and

[0009] FIGS. 4-5 show diagrammatically certain alternative embodimentsof the articulated arm system relating to the invention.

[0010] According to FIG. 1, the articulated arm system 20 comprises afirst parallelogram device 15 a, a spacing piece 10 and a secondparallelogram device 15 b. The first parallelogram device 15 a isattached through a connecting piece 18 and articulation pieces 13 and 12to a support structure 14, for example, a wall or a pillar. At the freeend of the second parallelogram device 15 b is attached the desiredimaging device 11, for example, an intraoral imaging device, through aconnecting piece 19. Both parallelogram devices 15 a, 15 b compriseparallel strut bars 6, 7 which are connected to the spacing piece 10 andthe connecting pieces 18 and 19 by means of articulations 8 a and 8 b.The mutual distance between the pivots 8 a in the connecting piece 18 ofthe parallelogram device 15 a is equal to the mutual distance betweenthe pivots 8 b in the spacing piece 10, and correspondingly, the mutualdistance between the pivots 8 a in the parallelogram device 15 b isequal to the mutual distance between the pivots 8 b. This means thatwhen the articulated arm is used for adjusting the device 11 into thecorrect position, the spacing piece 10 will remain in essentially thesame position throughout; in the case shown, the spacing piece 10 isessentially horizontal throughout.

[0011] In the embodiment shown in FIG. 1, both parallelogram deviceshave a counterbalancing mechanism with an additional strut bar 1, aroundwhich there is a counterbalancing spring 16 for holding the articulatedarm and the device supported by it in place. The additional strut bar 1is preferably ground and, in the embodiment shown, connected with bar 9in parallelogram device 15 a to the connecting piece 18 and inparallelogram device 15 b with the spacing piece 10. To preventunintentional movement of the articulated arm, in the solution relatingto the invention, braking and/or locking means have been mounted aroundthe additional strut bar 1. In the embodiment shown, these meanscomprise a locking piece 2 which includes a sleeve part surrounding theadditional strut bar 1. This piece 2 is connected to a lever arm 3 whichis loaded by force F to press the sleeve against the additional strutbar 1. In the embodiment shown, the force F is generated by means of thespring 4. In this solution, the locking is normally always on, and inorder to adjust the device into the desired position, at the end of thelever arm 3 are arranged actuators 5, for example, a solenoid, which ismade to pull by pressing the switch button 17 on the connecting piece19, whereby the lever arm 3 presses against the force of the spring 4,allowing easy movement of the additional strut bar 1 inside the sleevepart of the locking piece 2. The use of this locking piece 2 can also beimplemented vice versa, whereby the lever arm 3 is normally turned insuch a way that the additional strut bar 1 is able to move inside thesaid sleeve part, and when the articulated arm is to be locked, forexample, a solenoid 5 is used for turning the lever arm 3 in such a waythat the sleeve part presses against the additional strut bar 1. Insteadof a spring 4 and a solenoid 5, the actuator of the lever arm 3 may be,for example, a motor equipped with a self-locking worm gear, or evenmanual operation.

[0012]FIGS. 2 and 3 show an alternative friction-operated locking and/orbraking device acting on the additional strut bar 1, in which device aconical locking piece 22 is used instead of a sleeve, the said lockingpiece being provided with at least one axial gap which allowscircumferential movement of the locking piece in such a way that thelocking piece is pressed by means of the opposite conical piece 23loaded by the counterbalancing spring 16 against the surface of theadditional strut bar 1. Each gap may extend either over only a part ofthe axial length of the locking piece or over its entire length, whichmeans that the conical piece may also be comprised of two or moreseparate parts. To the conical piece 23 are attached lever arms 24 bymeans of joint pins 25, the lever arms forming a pliers-type means oneither side of the additional strut bar 1. By pressing the lever arms 24which are against each other at each time towards each other, theconical piece 23 is made to move away from the attachment with thelocking piece 22, which means that the additional strut bar 1 can moveeasily with respect to the locking piece 22. When the compression on thelever arms 24 ceases, the spring 16 loads the conical piece 23 backagainst the locking piece 22. The locking piece 22 may also be made ofan elastic material, for example, rubber, and its shape may also beother than conical. The elastic locking piece may extend uniformlyaround the additional strut bar 1, whereby elasticity will make possiblepressing it against the additional strut bar.

[0013]FIG. 4 shows another alternative embodiment in which thecounterbalancing mechanism of the parallelogram device is comprised ofthe lock-up air spring 30 arranged each time between the connectingpiece 18 or 19 and the strut bar 6. In this case, the additional strutbar 1 and the counterbalancing spring 16 connected to it can be omitted.Locking the air spring prevents the mutual linear movement of the strutbars 6 and 7 of the parallelogram device 15 a and 15 b, respectively.The air spring may also be arranged in only one parallelogram device,while the other is equipped with, for example, the counterbalancingmechanism shown in FIG. 1.

[0014]FIG. 5 shows yet another alternative embodiment which differs fromthe embodiment shown in FIG. 1 in that between the strut bars 6 and 7 ofthe parallelogram device is arranged a transverse lever 31 by means ofwhich the strut bars 6, 7 can be interlocked, in which case the means 2to 5 are omitted. The transverse lever may be, for example, a lock-uptelescopic lever which allows mutual linear movement of the strut barswhen the lever is not locked, for example, a lock-up air spring. As alever may also be used a rigid lever which is attached at least at oneend to the corresponding strut bar 6 or 7 in such a way that the saidend of the lever can move with respect to the strut bar when not locked,allowing mutual linear movement of the strut bars 6, 7, and when locked,will prevent the said mutual linear movement. This attachment of thetransverse lever to the strut bar may be realised, for example, byproviding the end of the transverse lever with a pin which moves in aguide groove or loop formed in the strut bar.

[0015] The embodiments described above are merely examples of certainpreferred implementations of the invention and are not intended to limitthe scope of protection of the invention defined in the appended claims.

1. An articulated arm system (20) for attaching different medicalimaging devices (11) to support structures (14) in an articulatedmanner, the articulated arm comprising at least one parallelogram device(15 a, 15 b) with at least two mutually parallel strut bars (6, 7); anda counterbalancing mechanism with at least one additional strut bar (1)and counterbalancing means (16) for holding the articulated arm and thedevice (11) supported by the articulated arm in place when the device islocated in the desired imaging position, characterised in that thesystem further comprises braking and/or locking means (2: 22) which acton at least one strut bar (6, 7) of the said at least one parallelogramdevice (15 a, 15 b) and/or on the said at least one additional strut bar(1) in order to prevent mutual linear movement of the strut bars (6, 7)of the parallelogram device, and which braking and/or locking meanscomprise actuators (3-5; 23; 24).
 2. An articulated arm system asclaimed in claim 1, characterised in that the braking and/or lockingmeans is a locking piece (2) surrounding the additional strut bar (1),the locking piece being equipped with a sleeve part through which theadditional strut bar (1) runs, which sleeve part can be brought intofriction attachment with the additional strut bar (1).
 3. An articulatedarm system as claimed in claim 1, characterised in that the lockingand/or braking means is a conical locking piece (22), which surroundsthe additional strut bar (1), and which locking piece can be made topress against the additional strut bar.
 4. An articulated arm system asclaimed in any of the claims 1 to 3, characterised in that the lockingand/or braking means is a locking piece (22) made of an elasticmaterial, which surrounds the additional strut bar (1) at least partly.5. An articulated arm system as claimed in any of the claims 2 to 4,characterised in that the actuator is a lever arm (3) which is connectedat one end to the braking and/locking means (2), and on the other end ofwhich is directed a loading force (F) by means of the actuators.
 6. Anarticulated arm system as claimed in claim 5, characterised in that theactuators are a spring (4) and a solenoid (5).
 7. An articulated armsystem as claimed in claim 5, characterised in that the actuator is amotor equipped with a self-locking worm gear.
 8. An articulated armsystem as claimed in claim 5, characterised in that the lever arm isoperated manually.
 9. An articulated arm system as claimed in claim 3 or4, characterised in that the actuator of the locking piece (22) is aconical piece (23) loaded by a counterbalancing spring (16), the conicalpiece being pressed against the locking piece (22) in order to bring itinto attachment with the strut bar (1).
 10. An articulated arm system asclaimed in claim 9, characterised in that the actuators further comprisea lever arm system (24) connected to the conical piece (23).
 11. Anarticulated arm system as claimed in claim 1, characterised in that as abraking and/or locking means, a transverse lever (31) is arrangedbetween the strut bars (6, 7) of the parallelogram device (15 a, 15 b),by means of which the strut bars (6, 7) can be interlocked, thuspreventing the said linear movement.
 12. An articulated arm system asclaimed in claim 11, characterised in that the transverse lever (31) isan air spring which can be locked into the desired position.
 13. Anarticulated arm system (20) for attaching different medical imagingdevices (11) to support structures (14) in an articulated manner, thearticulated arm comprising at least one parallelogram device (15 a, 15b) with at least two mutually parallel strut bars (6, 7); and acounterbalancing mechanism for holding the articulated arm and thedevice (11) supported by the articulated arm in place when the device islocated in the desired imaging position, characterised in that thecounterbalancing mechanism is comprised of an air spring (30) arrangedbetween one strut bar (6) and an articulated part, which air spring canbe locked into the desired position, thus preventing the mutual linearmovement of the strut bars (6, 7) of the parallelogram device.